User Manual
Table Of Contents
User’s Manual
Version 1.0, Nov. 2022
5
7． Appendix
7.1 The detection of the number of RSP-path
This section briefly explains the algorithm for the detection of the number of RSP-path.
The number of RSP-path is detected from the dataset of Geometry_data/Obs_time,
which gives the time from the epoch of UT00:00 at the date of the Granule ID, by using
the nominal parameters of the satellite orbit.
Let the t
d
be the time in the above dataset and t
d0
is the epoch time of the Granule ID,
the number of RSP-path P is given as the following formula,
=
+
+
(
)
1, + 1
where, mod(a,b) is the remainder of a division of a by b, int() is a conversion to an
integer with rounding-down, P
0
is the reference number of RSP-path, t
REF
is the
passing time of the ascending node of P
0
, N is the recurrent period, X is the total
number of RSP-paths, and t
ORB
is the period of orbit cycle. The setting of these nominal
orbital parameters are as follows:
P
0
= 196
t
REF
= 2018-01-16 07:57:14 (UT)
N = 34
X = 485
t
ORB
= N/X*86400
The actual satellite orbit has errors in the passing time of the ascending node from the
nominal, hence, it may cause a miss-detection of the RSP-path number in ascending
tiles around the equator. To detect and correct the miss-detection, a relative time
difference t
d
-
AN
between the observation and the ascending node is calculated as
=
+
where, t
AN
is the nominal passing time of the ascending node and is calculated as